Semiconductor devices are ubiquitous in modern electronic products. Semiconductor devices vary in the number and density of electrical components. Discrete semiconductor devices generally contain one type of electrical component, e.g., light emitting diode (LED), transistor, resistor, capacitor, and inductor. Integrated semiconductor devices typically contain hundreds to millions of electrical components. Examples of integrated semiconductor devices include microcontrollers, microprocessors, charged-coupled devices (CCDs), solar cells, and digital micro-mirror devices (DMDs).
Semiconductor devices perform a wide range of functions such as high-speed calculations, transmitting and receiving electromagnetic signals, controlling electronic devices, transforming sunlight to electricity, and creating visual projections for television displays.
In the case of devices that either generate or detect light in the visible spectrum, Indium Gallium Nitride (InGaN)-based devices are useful as they can be configured to be sensitive to or generate electromagnetic radiation throughout the visual spectrum. This broad range of operation makes the devices well suited to LED and laser applications.
The particular wavelength of operation of an InGaN device is selected by adjusting the amounts of Indium Nitride (InN) and Gallium Nitride (GaN) contained within the alloy that forms the active part of the device, such as a portion of a diode. When manufacturing these devices, however, the formation of structures that are made from the alloy can be difficult. This is because as more Indium is incorporated into the InGaN alloy, the strain in the InGaN layers increases due to lattice mismatch with the underlying GaN. This can cause defects such as dislocations or cracks in the alloy. In addition, the high strain can cause phase separation so that the InGaN is no longer homogeneous. Such phase separation can make it impossible or difficult to fabricate certain types of devices in a manner in which they operate properly. For example, when conventional methods are used to fabricate green-yellow light emitting or absorbing devices, the InGaN alloy layers may not emit or absorb light in the desired green-yellow optical wavelength range.